Peroxidases (E.C. 1.11.1.7) are enzymes that catalyse the oxidation of a substrate (an electron or hydrogen donor) with hydrogen peroxide. Such enzymes are known from microbial, plant and animal origins, e.g. peroxidase from Coprinus cinereus (cf. e.g. EP Patent Application 179,486). They are typically hemoproteins, i.e. they contain a heme as a prosthetic group.
Use of peroxidase together with hydrogen peroxide or a hydrogen peroxide precursor has been suggested e.g. in bleaching of pulp for paper production, in treatment of waste water from pulp production, for improved bleaching in laundry detergents, for dye transfer inhibition during laundering, and for lignin modification, e.g. in particle board production.
Peroxidase systems (also designated POD systems) comprising an enzyme exhibiting peroxidase activity, a source of hydrogen peroxide, and a peroxidase enhancing agent, are used for preventing surplus dyes from coloured fabrics which leach from the fabrics when these are washed from being deposited on other fabrics present in the same wash (this phenomenon is commonly known as dye transfer). Detergent compositions or wash liquors comprising such peroxidase systems have been described in WO 92/18687 and WO 92/18683.
A major drawback in applying such peroxidase systems to detergent compositions is that the enzymes present in such compositions may be strongly affected by the peroxidase system, thereby hampering the washing performance of the detergent composition.